부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.jsbmb.2005.06.028 Byline: Jin-Oh Kwak (a), Hyun-Woo Kim (a), Kwang-Jin Oh (a), Chang-Bo Ko (b), Hwayong Park (c), Seok Ho Cha (a) Keywords: Organic anion transporter 5; Steroid sulfate; Kidney; Immunohistochemistry Abstract: A family of organic anion transporters (OAT) recently identified has important roles for the excretion or reabsorption of endogenous and exogenous compounds, and several new isoforms have been reported in this decade. Although the transepithelial transport properties of organic anions are gradually being understood, many portions of their functional characteristics in functions remain to be elucidated. A recently reported new cDNA encoding a mouse OAT5 (mOAT5) was constructed, using 3'-RACE PCR, with the total RNA isolated from a mouse kidney. When mOAT5 was expressed in Xenopus oocytes, mOAT5 transported estrone sulfate, dehydroepiandrosterone sulfate and ochratoxin A. Estrone sulfate uptake by mOAT5 displayed a time-dependent and sodium-independent manner. The K.sub.m values of estrone sulfate and dehydroepiandrosterone sulfate were 2.2 and 3.8[mu]M, respectively. mOAT5 interacted with chemically heterogeneous steroid or organic sulfates, such as nitrophenyl sulfate, methylumbelliferyl sulfate and estradiol sulfates. In contrast to the sulfate conjugates, mOAT5-mediated estrone sulfate uptake was not inhibited by the steroid or organic glucuronides. The mOAT5 protein having about 85kDa molecular weight was shown to be mainly localized in the apical membrane of the proximal tubules of the outer medulla. These results suggest an important role of mOAT5 for the excretion or reabsorption of steroid sulfates in the kidney. Author Affiliation: (a) Department of Pharmacology and Toxicology, College of Medicine, Inha University, 7-241 Shinheung-dong, Jung-gu, Incheon 400-712, Republic of Korea (b) Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Republic of Korea (c) Department of Biology, Chungnam National University, Daejeon 305-764, Republic of Korea Article History: Received 2 March 2005; Accepted 13 June 2005